1. Field of the Invention
The invention relates to an ink jet recording method and an ink jet recording device, and specifically relates to an ink jet recording method and an ink jet recording device favorably used for forming a high-quality image at high-speed.
2. Description of the Related Art
An ink jet method of ejecting ink in the form of liquid droplets from an ink ejector has been used in various kinds of printers for the reasons of being compact and less expensive, capable of forming an image without contacting a recording medium, or the like. Among these ink jet methods, there are a piezo ink jet method utilizing deformation of piezoelectric elements to eject ink and a thermal ink jet method utilizing boiling phenomenon of ink due to thermal energy to eject ink in droplets, which have the characteristics of high resolution and high-speed printability.
Improvements of speed and image quality have currently become important objectives, upon printing by ejecting ink droplets onto a plain paper sheet or a non-water absorbing recording medium made of plastics or the like with an ink jet printer.
Ink jet recording is a method of ejecting ink droplets according to image data to form a line or an image on a recording medium with the liquid droplets. However, there have been problems in practical use, particularly in the case of recording on the above described non-absorbing recording medium, e.g., bleeding of an image easily occurs, or mixing of adjacent ink droplets occurs on the recording medium to inhibit formation of a sharp image, when it takes time for the liquid droplets to dry or penetrate into the recording medium after being ejected. When the liquid droplets mix with each other, ejected adjacent liquid droplets coalesce with each other to shift from the positions at which they have landed, thereby causing unevenness in line width in a case of forming fine lines or unevenness in color in a case of forming a colored area, or the like. Further, since the degree of occurrence of unevenness in line width or color unevenness in a colored area varies depending on ink absorption and wettability of the surface of the recording medium, there has also been a problem that different images are formed among various types of recording media, even though the same ink is used under the same ejection conditions.
As a method of suppressing image bleeding or nonuniformity of line width, there is a method of promoting fixation of liquid droplets. For example, there have been disclosed the methods of using inks of two-liquid type having reactivity and allowing them to react with each other on a recording medium to achieve a describing property with high definition, such as a method of recording with ink containing an anionic dye after application of a liquid containing a basic polymer (for example, refer to Japanese Patent Application Laid-Open (JP-A) No. 63-60783), or a method of applying ink containing an anionic compound and a coloring material after application of a liquid composition containing a cationic substance (for example, refer to JP-A No. 8-174997).
An ink jet recording method has also been proposed in which an ultraviolet-curable ink is used as the ink, and the ejected ink dots on a recording medium are irradiated with an ultraviolet ray in conformity with the timing of ejection, then the dots are pre-cured to be thickened to such an extent that the adjacent dots do not mix with each other, and thereafter the dots are further irradiated with an ultraviolet ray to complete curing (for example, refer to JP-A No. 2004-42548).
Further, a method has been proposed that improves visibility or bleeding of color ink and the problem such as variation in the obtained images formed on different types of recording media, by applying a radiation curable white ink to form a uniform undercoating layer onto a transparent or a semi-transparent non-absorbing recording medium, then curing or thickening the layer by irradiating with a radiation ray, thereafter recording with a radiation curable color ink (for example, refer to JP-A No. 2003-145745 and JP-A No. 2004-42525). There has also been proposed a method in which a substantially transparent active ray-curable ink is applied onto a recording medium in place of the radiation curable white ink by an ink jet head (for example, refer to JP-A No. 2005-96254).
However, in the method described in JP-A No. 2004-42548, although blurring can be suppressed, there still remains the problem of variation in images among various types of recording media, and thus the problem of unevenness in line width, color or the like due to mixing of ink droplets are not sufficiently solved. This problem of unevenness in line width, color or the like due to mixing of ink droplets are also not sufficiently solved by any of the methods described in JP-A No. 2003-145745, JP-A No. 2004-42525. Further, there sill remains a problem of unevenness in line width, color or the like due to mixing of ink droplets in the method described in JP-A No. 2005-96254.